A skills assessment is the list of questions behind each automated interview.
Automated interviews are completed by candidates "on demand" rather than live, so the questions need to be prepared in advance. You can choose different question and answer types and decide whether to apply a time limit to each question.
As a guide, you should aim to have around ten questions in a standard skills assessment.
For complete instructions on how to add or create a assessment go here.
For tips on how to write an effective skills assessment, read here.